While I was patiently waiting for Amazon to deliver my package, I went ahead and started planning out where I wanted my other two pieces of background decoration to be. I then siliconed the cork piece to the background, just like I did with the main centerpiece. The hunk of bark I actually want to lay on the wet foam, since it's already pretty flat, so I'll just line it up on the glass for now.
Anyways, back to foaming. Fortunately wet Great Stuff sticks well to dried Great Stuff, so there's no need to do anything other than spray on like last time.
After about 15 minutes or so, I'm done!
You'll notice I left about 4 inches of space between the bottom and the foam - that'll be where the substrate/drainage layers go up to, so there's no need to foam down that far. Now we just gotta let this bad boy dry. Shouldn't take longer than a day. Next step - trimming it down. I'll update once I'm ready to do some cuttin'.